Lewis wilkinson



. @einen :taire @anni @fitta LEWIS WiLKIN'SoN, or BOSTON, MASSACHUSETTS.

Letters Patent No. fi 8,850, dated June 9, 1868.

IMPROVED BALL-CASTLE.

dige Stimuli entre tu in ligen Etains trinit :uw meting ont it tigt izmir.

'lO ALL WHOM l'l MAY OONCERN:

Be it known that I, Lewis WILKINSON, of Boston, in the county of Suffolk, and State of Massachusetts, have invented an Improved Ball-Caster; and I do hereby declare that lthe following, taken in connection with the drawings which accompany and form part of this specification is a description of my invention suiicient to enable those skilled in the art to practise it.

My invention has reference to that class of furniture-casters known as .balhcasters, in which the frictionroll consists of a spherical ball, so combined with a socket or seat, as to roll freely in every direction.

My improvement relates, particularly. to the manner of applying and holding the ball within its seat or socket; and the invention consists, primarily,oin making the socket in'thc forni of an inverted cup, provided with suitable bearing-points yor surfaces for the upper side of' the ball to rest against, and having four or any other suitable number of extensions projecting to such depth that by springing them inwards slightly, they ser've to retain the ball in the socket, so that it cannot drop ontby gravity when the caster is raised, while by slight strain or pressure, tho ball may be readily withdrawn from erpressed into the socket` The drawing represents at A a vertical sectionl of my improved caster. B shows a bottom view ofthe ballcontaining socket. l

a denotes the ball-containing' cupor socket, attached by a neck, 6, to a flanged circular disk or plate, c, which lits upon thebottonl ofthe table or other leg, to which the castor` is to be applied, the caster being secured to the ,leg by a central screw-spindle, d, risinglfrom the plate c, as seen at A, this screw-spindle being for the purpose of entering the leg, and securing the ball-socket firmly thereto.

Within the socket, at the upper surf-ace thereof, are small projections, c, against the points oi' which. the b all rests and rotates. I

fdenotes the ball, which fits loosely in thgupper part of the cup or socket, and bears at top only against the pointsot' the `pins e.

Projecting down, at opposite sides of the` socket, are extensions y, which reach belowa horizontal plane passing through the centre oi' the ball, and are bent inwardly, as seen at A and B, so that from the point of one to the point of its opposite is a little less than "the `diameter of the ball, orso much so that while the ball may be readily pressed through them to remove it from or place it in the cup e, the points will secure it from dropping out when the easter isilifted off the door. l

Ball-casters are generally somewhat complex in construction, andA are therefore expensive, and easily get out oi' order, but the simplicity Vof my construction, and the ease with which the ball may be applied or removed, render the article superior both in eiliciency and in cheapness to any construction now to me known.

The whole hall-eontaining'device is made in one piece, provided with its own means ofattachment to the table-leg, withontnecessity for employmentI ot"l any auxiliary screws or other fastening-devices, the screw. spindle bringing the plate c up tightly against the bottom of the leg, the plateand its flange imparting a.s`ubstautial and ornamental finish tothe bottom of the leg and the top of the easter.

For light furniture, the screw-spindle may be dispensed with, the plate ,c being then screwed to the bottom of the leg with c omrnon screws, but I generally Iprefer the construction shown. i

The advantage of the ball-caster, in running freely in every direction, over the wheel-caster, which has to swing in a vertical shaft, well known, and need not be described.

I claim a furniture-easter, having a ball,f, secured in a cup or socket, a, by extensions g, substantiallyas shown and described.

I also claim, in combination with such socket a and extensions g, the pins orr projectiohs e, against which the surface of the ball bears and rotates, substantially as shown and described. l j

I also claim, in combination with the ball-containing cup or socket, the flanged plate or disk e, and screw spindle cl, cast integral with Vthe socket-piece, substantially ,as` described.

LEWIS WILKINSON.

Witnesses:

J. B. CROSBY, FRANCIS Gonne. 

